This invention relates in general to apparatus for filtering internal combustion engine intake air and, more specifically to an assembly that functions both to filter engine intake air and to collect and condense oil in fumes from the crankcase breather port.
A variety of different air filters have been designed over the years for filtering dust and the like out of engine inlet air to prevent the dust from entering the combustion chambers. Since abrasive dust can rapidly abrade engine components such as pistons, piston rings, valves, etc., it is important that the air filters have very high efficiency.
Many conventional engine air filters use an annular filter in a housing with air entering from an inlet to the filter exterior and passing to a carburetor connected to the filter interior. These filters have been developed to the point where they are quite effective. Some filters are used dry and some are coated with oil to increase entrapment of very fine particles. This filter design, however, is rather large and occupies an undesirably large volume in the engine compartment. Also, this large ring-like arrangement is not optimized for use with fuel injected engines, in particular diesel engines. Further, with the oil coated embodiment, it is difficult to maintain a uniform continuous very light oil coating at all times.
Slender, elongated, air filters having a frustum-shaped filter element have been developed, such as that described by Tokar et al. in U.S. Pat. No. 4,211,543. While these filters take up less engine compartment space than do annular filters, still there is no method for maintaining a slight, uniform and constant oil film to trap very fine particles.
Another problem in modern engines, both diesel and gasoline engines, is handling oil vapor and droplet containing fumes from crankcase breathers without emitting environmentally undesirable oil and other material into the atmosphere. Allowing these fumes to be simply be ducted to the atmosphere is no longer acceptable. Attempts have been made to capture these fumes and oil droplets in filters, condensing canisters, etc. with little success. Generally, these fumes are simply directed into the engine intake air and fed to the engine combustion chambers. This can result in poorly running engines, spark plug fouling (in spark ignition gasoline engines and the like), catalytic converter and fuel injector fouling, increased undesirable exhaust emissions. Other problems are caused as the air cleaner plugs up causing the draw on the crankcase to increase resulting in oil passing to the intake and cylinders.
Thus, there is a continuing need for internal combustion systems that prevent fine dust particles and excessive oil in crankcase breather fumes from entering the engine with intake air to reduce engine wear and oil fouling of components and improve the quality of exhaust gases entering the environment.